Frontinus, who wrote in the time of Nerva and Trajan, mentions (as we have seen) nine aqueducts[202], reckoning as distinct several branches, or additional channels, subordinate to others more important. There is one more important record to which reference has not hitherto been made, namely, the summary at the end of the _Curiosum_ and _Notitia_, in which nineteen are enumerated. The entry in the Summary of the Regionary Catalogue is as follows:— Aquæ XIX. I. Traiana [X.] II. Annia (or Anio Vetus?) [II.] III. Attica (Anio Novus) [IX.] IV. Marcia [III.] V. Claudia [VIII.] VI. Herculea [XVII. Almo?] VII. Cerulea [IX.] VIII. Julia [V.] IX. Augustea [I.] X. Appia [I.] XI. Alseatina [VII.] XII. Ciminia (?). XIII. Aurelia [XII.] XIV. Damnata (Cloaca Maxima?). XV. Virgo [VI.] XVI. Tepula [IV.] XVII. Severiana [XIII.] XVIII. Antoniana [XIV.] XIX. Alexandrina [XV.] Those not previously mentioned are (1.) Attica, (2.) Herculea, (3.) Cerulea, (4.) Augustea, (5.) Ciminia, (6.) Damnata. 1. Attica is supposed by Fabretti to be the same as Alseatina [VII.], but then how is the number of nineteen to be made up? It was probably the Anio Novus, as already described. [See IX.] 2. Herculea. This is mentioned by Frontinus[203] as receiving a part of the Aqua Marcia after its entrance into the city[204]. Another stream of the same name, thirty-eight miles from the city, was added to the Anio Novus[205]; but it seems most probable that the stream here intended is the Almo, which enters Rome under the Porta Metronia, and conveys the water of the Marrana, or Aqua Crabra, coming from these two mountain-streams united, as already described. This is always a very strong stream. It follows the line of the aqueducts for miles towards Rome, and received the surplus water in many places, where there were _piscinæ_; it passes very near to the point where the aqueducts enter Rome at the Porta Maggiore, and may very well have received the surplus water there also of the Marcia, as stated by Frontinus. 3. Cerulea. This is the name of one of the branches of the Claudia, among its sources, and is mentioned in the inscription at the Porta Maggiore; but again, this does not account for one of the nineteen Aquæ. 4. Augustea. A stream was added to the Aqua Marcia by Augustus, and called after him[206]; but that would not account for another stream in Rome here indicated as one of the nineteen Aquæ. It is more probable that the water here intended is the Augustan branch of the Aqua Appia, which was united at the Gemelli within the outer wall of Rome. Frontinus (c. 4), indeed, mentions that the Alseatina was also called Augustea, but that would not account for another of the nineteen streams[207].