38 



BIOLOGICAL RESULTS OF LAST CRUISE OF CARNEGIE 



Genus CALLIZONELLA Apstein 



Callizonella pigmenta n. sp. 



(Plate II, figure 25) 



The following description is tentatively offered for a 

 new species of this genus, of which a very few appeared 

 in the collections. The body is about 5 mm long and not 

 over 0.5 mm wide in the widest part, which is about the 

 middle region. From here there is a very decided ta- 

 pering to the pygidium. The most noticeable feature is 

 a deposit of black pigment on the dorsal face of the 

 first five somites, a color character easily visible to the 

 naked eye. The eyes (pi. II, fig. 25) are very large and 

 separated from one another by a narrow but relatively 

 deep depression. Apparently the lenses normally are 

 pointed ventrally but distortions are so easy in the case 

 of the eyes that the author is not certain this is the case, 

 or whether the condition is a result of preservation and 

 mounting. He could find no median tentacle. 



On either side of the first somite is a ventral tenta- 

 cular cirrus which is covered over by the very large 

 pigmented cirrophore of the dorsal tentacular cirrus of 

 the second somite. Of the tentacular cirri of the second 

 pair, the ventral one is similar in size and form to that 

 of the first. Because of distortion and poor preserva- 

 tion it is impossible to be certain, but apparently the 

 third pair of tentacular cirri is a small dorsal and much 

 larger ventral one, the bases of the latter nearly meet- 

 ing on the ventral surface. In the following somites the 

 ventral cirri are similar to the smaller ones of the ven- 

 tral tentacular cirri. 



The pigment above mentioned ceases abruptly on the 

 posterior border of the fifth setigerous somite. The 

 parapodia are acutely conical at the apices and each has 

 the terminal cirrus characteristic of the genus. As the 

 body narrows posteriorly, the parapodia retain their 

 length and at the same time become more slender so that 

 they are very prominent. No cirri were to be found. 

 The setae are of two kinds, capillary and crochets. They 

 are both very long, especially those in posterior somites 

 where they are longer than the l)ody diameter. In these 

 posterior somites the crochets are more numerous with 

 reference to the capillary than is the case farther for- 

 ward. 



The type is no. 20088 in the United States National 

 Museum and was collected at station 151 in 50 m. See 

 map 3 (p. 58). 



A fragment of a specimen of this genus was taken in 

 50 m at station 23. 



FAMILY TYPHLOSCOLECIDAE 



Genus TYPHLOSCOLEX Busch 



Typhloscolex mulleri Busch 



(Plate II, figure 27) 



Typhloscolex mulleri, Busch, 1851. 

 Typhloscolex mulleri, Reibisch, 1895, pp. 52-53; pi. 5, 

 figs. 1-5. 



The identification was by means of the descriptions 

 given by Reibisch. 



Stations and depths of collections were as follows: 



See map 4, p. 59. Indeterminable species of this 

 genus were taken at the surface at stations 31 and 36, 

 and in 100 m at 22 and 71. 



Genus PLOTOBIA Chamberlin 



Plotobia simplex Chamberlin 



Plotobia simplex Chamberlin, 1919, pp. 155-156, pi. 65, 

 figs. 6-11; pi. 66, fig. 1, 



Collected in 50 m at station 122 and in 100 m at sta- 

 tions 120 and 123. The record shows that one was taken 

 at station 64 in 1000 m. This probably should read 100 m. 



Plotobia pauclchaeta n. sp. 

 (Plate n, figure 26) 



As defined by Chamberlin (1919, p. 152) this genus 

 is characterized by the possession of a dorsal pair of 

 nuchal organs, which in one of his two species is 

 branched and in the other cirriform. The cirrus-like 

 structures on the dorsal prostomial surface of these 

 specimens seem to be homologous with Chamberlin's 

 nuchal organs and the author has accordingly placed 

 them in the genus Plotobia. 



The type is 3.5 mm long and the prostomium is blunt- 

 ly rounded but in others it carries the characteristic 

 pointed tentacle (plate II, fig. 26). Dorsally the prosto- 

 mium is elevated and on either side is a broad cirrus. 

 The rounded nuchal organs lie on the dorsal surface and 

 there are no eyes. 



Along the side of the body are twenty pairs of plate- 

 like cirri which are broadly lanceolate in outline and are 

 largest near the middle of the body except that the anal 

 pair are very large and broad. The posterior somites 

 are short and in consequence the posterior cirri are 

 much crowded together. The only setae in the body are 

 on the last three somites, immediately in front of the 

 pygidium. The author was unable to find any setae at all 

 in the type, but they occur in other specimens. In each 

 seta tuft are two stout, colorless, and slightly bent setae. 



