108 BULLETIN OF THE 



procured. My attention in the following observations was chiefly di- 

 rected to the growth of the hard parts of the body, often called the 

 skeleton, while observations on the bilateral larva are simply introduced 

 as they are thought to throw light on some of the many obscure ques- 

 tions in relation to this part of the subject. 



I. GENERAL OBSERVATIONS. 



Many observers have called attention to the fact that A. squamata is 

 viviparous. No one, so far as the literature has been studied, has seen 

 the young in the American shallow-water Amphiura, although Lyman 

 and others have shown its undoubted identity with the European, 

 A. squamata. Of the other species of Amphiura which live in our waters 

 no one has studied the development. 



Metschnikoff * has shown that A. squamata is hermaphrodite. This 

 observation has been verified by Apostolides,t and I have found the 

 male genital glands in the Newport specimens in the same position as 

 figured by Metschnikoff t in the European. Almost every specimen of 

 Amphiura which was collected in August and September was found to 

 contain young, while some had the male glands with lively sperm and 

 young in various stages of growth in the same individual. This fact 

 may look like self-fertilization. It remains to be seen, however, whether 

 the sperm from one individual can impregnate its own ova, or whether 

 this product from another specimen is required for this function. I am 

 not aware that any one has yet succeeded in artificially impregnating an 

 Amphiura with its own sperm. Self-fertilization may take place, but no 

 one has yet recorded it. 



My specimens of the adults were found in crevices of the cliffs just 

 below low-water mark. We found good collecting-grounds on the south 

 end of Castle Hill, at Price's Neck, and near Horse's Head, Conanicut 

 Island. The adults prefer a bottom composed of broken Mytilus shells 

 and small stones. Lyman § has already spoken of their preference for 

 a bottom of broken shells. With a long-handled dip-net a few handfuls 

 of this bottom can be scraped up from the crevices, and the adults can be 

 easily picked out of the fragments of shells with pincers. 



* Studien iibcr die Entwickelung der Echinodermen und Nemertinen, Mem. 

 de VAcad. Imp. des Sci. de St. Petersb., [7] XIV. 8, pp. 13, 14 (separate copy). 



t 1* These. Anatonne et Developpeiueiit des Ophiures, Arch, dc Zool. Exp. et 

 (?e,>.., X. p. 204. 



X Op. cit., PL III. Fig. 1, B. Our Amphiura squamata is also hermaphrodite. 



§ Ophiuridae and Astrophytidae, III. Cat. Mus. Comp. Zool., No. 1. 



