150 JOUENAL OF THE NEW JERSEY 



1. Chseto}jleura cqnculata, Siiy . (Fig. 44). Form oblong-oval, 

 convex; valves obtusely keeled, the central portion of the pos- 

 terior margin becoming slightly beaked with age ; lateral areas 

 triangulai, studded with numerous rounded tubercles, obsolete 

 towards the apices, more numerous towards the sides ; these 

 sides are rounded, with an elevated, marginal line ; middle space 

 lozenge-shaped, and covered with 10 or 12 rows of elevated, 

 rounded dots on each side of the keel, and parallel with it. 

 Grayish, bluish, or ferruginous. L. 13-25 ; W. 8-15. — Whole 

 coast. More abundant southerly. 



3. ToNicELLA, Carpenter. 



Anterior and posterior plates, as in the preceding ; surface of 

 girdle, smooth or minutely downy; eaves short; gills medium. 



1. Tonicella marmoreus, Fabr. Shell oblong-ovate, rather flat ; 

 valves slightly keeled and beaked, their surface covered with 

 microscopic granulations in quincunx order ; to the naked eye, 

 smooth and shining ; girdle covered with a close, short down, 

 alternately white and red. Color varying from bright red to 

 yellowish or dark brown, with numerous fine, zigzag wdiitish 

 lines over the whole surface ; posterior edge of valves with 6-8 

 whitish spots. L. 17; W. 11. Cape Cod and north. 

 CLASS III, CEPHALOPODA. 



Free swimming, oceanic mollusks with well-marked head, and 

 a circle of muscular arms around the mouth, by the aid of which 

 they move freely from place to place. These arms are usually 

 supplied w4th suckers ; the eyes are large and very perfect ; the 

 mouth provided with two long, beak-like jaws. Sexes distinct. 



ORDim DiBRANCHIATA. 



Cephalopoda with two gills in the mantle cavity ; eight or ten 

 arms provided with suckers ; an ink bag, for the secretion of a 

 black fluid, always present. This is used to color the water 

 when pursued. The species given in this work all belong to the 

 suborder Decapoda having 8 true arms, which are sessile, and 2 

 long tentacles, which have a stalk and clubbed ends ; the suckers 

 are stalked, and have a horny rim. The mantle bears two lat- 

 eral fins. An mternal shell is alway present, and is usually 

 horny in substance, and feather or lance-like in form. 

 Family 71. SPIRULID/E. 



This family consists only of the genus : — 



