MUSEUM OF COMPARATIVE ZOOLOGY. 17 



the stomach, and sending one vessel in the haemal direction along the 

 median line of the stomach, and another on each side laterally. It is 

 attached by its lesser extremity, and, contracted by the alcohol, appears 

 exceedingly minute. A very careful search failed to reveal any accessory 

 pulsatile vesicles, yet it is possible that, from their extremely small size, 

 they may have been overlooked. The ovaries are very limited in extent 

 and principally confined to that portion of the sinuses which surrounds 

 the visceral cavity, only their ultimate extremities entering the larger 

 branches of the great sinuses. Those in the haemal valve are vermiform, 

 slightly hooked at their posterior extremity. Those in the neural valve 

 form open loops, with the " bight " posterior, and the two anterior extrem- 

 ities just entering the two outer sinuses. Their manner of suspension is 

 the same as in the other species of the genus. The ova were visible in all 

 stages of growth. Those floating free in the lacunes were nearly spherical, 

 and of a flesh color ; their substance seemed of a granular consistency, due 

 perhaps to the action of the spirit in which they were preserved. The 

 immature ova were pyriform, attached to the ovary by their pointed ends. 

 With the yellowish matter of the ovary were interspersed specks of a 

 brownish granular matter, which appeared dark yellowish under a high 

 power and intermixed with what seemed to be fat-globules; Somewhat 

 similar specks were observed in the hepatic matter. This was more 

 abundant toward the middle line of the ovary, but was irregularly distrib- 

 uted. No spermatophorae or spermatozoa were observed in any of the 

 specimens examined. The oviducts were situated as in W. australis. The 

 lining membrane of their trumpet-shaped portion was .drawn into thin 

 plicae. Their apices were teat-shaped, with very small orifices. 



The mantle margin is folded as in other species ; the fold is deeper in 

 the sides than'in front, and not wide anywhere. The setae are very slender 

 and fine, irregularly marked with transverse lines, but smoother toward 

 their outer ends. They protrude from their follicles, hardly more than one 

 third of their length. In no instance was more than one seen to issue 

 from a single follicle. The circumpallial muscular band is very slender 

 and narrow. No coloring matter was observed in or about the follicles. 

 The mantle edge was brownish, and seemed to have a slightly villous epi- 

 thelium. No setellae, such as I have elsewhere described as existing on the 

 setae of Discina and Lingula, were to be found. 



I did not observe any noticeable peculiarity in the perforations of the 

 shell-structure. The " suture " or breaking point, described by Messrs. 

 Jeffreys and Carpenter in W. cranium, exists in all the species with a 

 reflected loop, and is due to the deposition of the shelly matter of the loop 

 in laminae parallel with the longer axis of the shell, which makes the loop 

 weaker at the point of reflection than elsewhere. 



VOL. II. 2 



