ALASKA NEMERTEANS II 



4. Head and anterior portions of body narrow and slender, with remarkably 



long and deep cephalic furrows. Dark brown or purplish, paler 

 on borders of cephalic slits and tip of snout C. longicefs, p. 77. 



5. Very long and ribbon-like, becoming 2 meters or more in length. Deep 



blood-red except tip of snout, which is yellowish white both above and 

 below C. montg'omeryt, p. 80. 



6. Reddish purple except head which is white on both dorsal and ventral 



surfaces back to anterior border of mouth C albt/rons, p. 82. 



SYSTEMATIC DISCUSSION OF GENERA AND SPECIES. 



Carinella Johnston. 

 Mag. Nat. Hist. London, vi, p. 232, 1833. 



The species belonging to this genus are characterized by a slender, 

 soft, rounded body, capable of extending and contracting to a remark- 

 able degree. Head distinctly marked off from body, usually much 

 broader than parts immediately following, often flattened dorso-ven- 

 trally, and disk-like. 



On each side of body a transverse furrow separates the head from 

 the esophagal region. Proboscis opening subterminal ; mouth a small 

 round opening on ventral surface just back of lateral transverse furrows. 

 The lateral nerves lie outside the muscular layers of the body, and 

 just beneath the basement layer of the integument. The body walls are 

 made up of a very thick outer epithelium with abundant glands, a 

 basement layer, a circular muscular layer, and a longitudinal muscular 

 layer in the order named from without inwards. In addition to these 

 there is, in the esophagal region, an inner circular muscular layer 

 which often forms a dorsal, and sometimes a ventral crossing with the 

 fibers of the outer circular muscular layer. 



Proboscis sheath usually not more than Yi the length of body. 

 Proboscis small and short. Ocelli wanting. Cerebral sense organs 

 usually represented simply by a pair of sensory pits in the epithelium, 

 although some species (cf. C. speciosa) possess a pair of well-devel- 

 oped sense organs with ciliated canal, ganglion cells and glands. A 

 pair of peculiar lateral sense organs is usually situated well back in 

 the esophagal region. Some of the species show elaborate markings 

 of fine white lines on a brownish body, others are homogeneous in 

 color. Most species are colored in some shade of brown or red ; 

 some are bright vermilion. 



I. CARINELLA SPECIOSA sp. nov. 

 pi. Ill, fig. 6; p1. IX, figs. 1-3; p1. X, figs, i, 2. 

 Body large, very long, flattened below, rounded above, and remark- 

 ably soft and pliable. This beautiful Nemertean closely resembles C. 



