_Mayer, P._ 1903 Siboga-Expeditie, xxxiv, Monographie, pp. 79-92. _Sars, G. O._ 1895 An account of the Crustacea of Norway, vol. i, Amphipoda, p. 663. _Say_ 1817 Journal of the Academy of Natural Science, Philadelphia, pp. 390-391. (_Contribution from the Zoological Laboratory of Pomona College_) EXPLANATION OF PLATES Plate I _C. geometrica_ (adult). ×25 Figure 1. Body showing length of segments Figure 2. First gnathopod. Figure 3. Second gnathopod. Figure 4. Fifth peræopod. Plate II _C. geometrica_ (young male). ×40 Plate III _C. geometrica_ (young male) Figure 5. Maxillipeds. ×300. Figure 6. Lip. ×300. Figure 7. First maxillæ. ×300. Figure 8. Second maxillæ. ×300. Figure 9. Mandible. ×300. Figure 10. First gnathopod. ×175. Figure 11. Second gnathopod. ×175. Plate IV _C. septentrionalis_ Figures 12, 13. Bodies, showing length of segments. ×25. Figure 14. Mandible. ×110. Figures 15, 16. Second gnathopods. ×25. Plate V _C. æquilibra_ Say Figure 12. Body showing length of segments. ×50. Figure 13. Projection at base of second gnathopod. ×150. Figure 14. Second gnathopod. ×150. Figure 15. Fifth peræopod. ×150. [Illustration: Plate I] [Illustration: Plate II] [Illustration: Plate III] [Illustration: Plate IV] [Illustration: Plate V] Record of Two Fish, Not Before Mentioned, from Laguna During the summer of 1914 no special effort was made to collect fish, but the two following species were taken: _Porichthys notatus_ Girard A specimen of this interesting but rather common Californian fish was taken in a tide pool and kept for some time alive in the aquarium. This is sometimes called "Midshipman," because of the bright metallic spots over the head and body, like the buttons on a midshipman's uniform of years ago. These spots are provided with a lens, connective tissue capsule and a reflector, and are supposed to be luminous. _Mola mola_ Linnæus A small specimen of this head-fish, or sunfish, was brought to us by the fisherman. W. A. H. Note on the Sea Urchins of Laguna Beach Due to the kindness of Dr. H. L. Clark of Harvard, we are able now to have some clearer idea about the number of species of sea urchins found at Laguna. _Strongylocentrotus purpuratus_ Stimp This is our most common species. It occurs by the hundreds in some of the larger tide pools, such as those near Seal Rocks. Judging from the specimens sent to Dr. Clark, the rather common greenish form, which we supposed to be distinct at first, is simply a younger form of the same species. This greenish form is more often found nearer shore under stones, where quite small individuals are abundant. [Illustration: