I have a half dozen of these from holdfasts. Sabellidæ Small sabellids are common in holdfasts and seaweed masses. Serpulidæ The calcareous tubes of these animals are seen everywhere below half tide, on rocks, in holdfasts and on kelp (spirobis). I have six different serpulids. Hermellidæ There are probably two species of this family common at Laguna. _Sabellaria californica_ Fewkes. This form was found in large colonies in the protected crevasses of cliffs west of the laboratory. The colonies are some twenty feet long, two feet wide and ten inches thick. The tubes are of loosely agglutinated sand and are crowded very closely together with their mouths evenly disposed over the surface of the colony. Another species lives singly in very hard, thick sand tubes. Some specimens have algæ growing on their opercula. Turbellaria I have three kinds of these "flat worms" in my collection. They are found under partly submerged stones. Nemertinea There are seven different nemertines in the collection. They are recorded from holdfasts, seaweed tangles and from among vermetus tubes. Nematoda There are two or three different marine nematodes in the collection. They are most common in the finer moss. Sipunculoidea There are two kinds of sipunculids, which seem quite distinct. Taken from eel-grass roots, from under rocks and mussels. The specimens were identified from the following papers: _Fewkes, J. W._ 1899 New Invertebrata from the Coast of California. Bull. Essex inst. xxi, 99-146, pls. 1-7 (2) figs. in text. _Johnson, H. P._ 1897 A Preliminary Account of the Marine Annelids of the Pacific Coast, with Descriptions of New Species. Proc. Cal. ac. sc. (3), i, 153-198, pls. 5-10. -------- 1901 The Polychætæ of the Puget Sound Region. Proc. Bost. soc. nat. hist., xxix, 381-437, pls. 1-19. _Moore, J. P._ 1904 New Polychætæ from California. Proc. acad. nat. sci., Philadelphia, 56-484-503, pls. 37-38. (_Contribution from the Zoological Laboratory of Pomona College._) Studies in the Comparative Size of the Red Blood Corpuscles of Birds CHI TSAU WANG The blood corpuscles of a large number of vertebrates were studied at Laguna Beach during the past summer. Some of the sizes of cell and nucleus are given below. The blood was obtained as fresh as possible; in no case was the blood obtained longer than twenty-four hours after death. The corpuscles were measured by the ocular micrometer and checked by the aid of a camera lucida.