Cerapus 



Synopsis of species : 



{Antenna 1, 1»* Joint distally widened — 2. 

 Antenna 1, Ist joint not distally widened — 3. 



J Antennae 1 and 2, flagella 2-jointed 1. C. erassicomis . . p. 666 



) Antennae 1 and 2, flagella 4- or 5-jointed ... 2. C. sismithi . . . p. 666 



f Antennae 1 and 2, flagella 3-jointed 3. C. tubularis . . . p. 667 



\ Antennae 1 and 2, flagella 4 — 6-jointed — 4. 



/ Antenna 1, 3d Joint of peduncle much longer 



J than 2d 4. C. flindersi . . . p. 668 



I ün 



than 2d — 5, 



j Antenna 1, 3^ Joint of peduncle not much longer 



/ Gnathopod 2 in (5, inner tooth of 5tli Joint 



J prominent, acute 5. C. abditus . . . . p. 668 



j Gnathopod 2 in (S, inner tooth of 5tli Joint not 



' " prominent, obtuse 6. C. calamicola . . p. 669 



1. C. crassioornis (Bäte) 1857 Siphonocetus c, Bäte in: Ann. nat. Hist., ser. 2 

 ».19 p. 149 I 1862 Siphonoecetes c, Bäte & Westwood, Brit. sess. Crust., v.l p. 469 f. | 

 1882 Cerapus c, G. O. Sars in: Forh. Selsk. Christian., nr. 18 p. 113 t. 6 f . 8 | 1893 C. c, 

 A. DellaValle in: F. Fl. Neapel, v.20 p. 378 t. 55 f. 52 | 1894 C. c, G. 0. Sars, Crust. 

 Norway, v. 1 p. 607 t. 217. 



Peraeon segmeuts 1 and 2 in Q shorter than any of the following 5; 

 but in ä Segment 1 is not shorter and segment 2 much longer. Head, 

 rostrum rather large, acute; lateral lobes short, obtuse. Side-plate 5 much 

 the largest, its front lobe broad and deep. Pleon segment 3, postero-lateral 

 Corners rounded. Eyes small, round, dark. Antennae 1 and 2 very setose, 

 Short, subequal. Antenna 1 the stouter, slightly the longer, nearly ^a as 

 long as body; P* Joint about as long as 2^ and S*^ combined, much broader, 

 widened distally and produced to a triangulär lobe over 2<* Joint, which is 

 as long as 3<^; flagellum scarcely longer than B*! Joint of peduncle, with 2 joints, 

 last minute. Antenna 2, ultimate and penultimate joints of peduncle sub- 

 equal; flagellum as in antenna 1. Gnathopod 1, 5*^ Joint nearly as long as 

 6*^ distally wide with setose lobe, 6*^ wide at base; palm oblique, scarcely 

 defined; finger long. Gnathopod 2 in d, 2'^ Joint expanded to a broad 

 oval, 5*^ large, scarcely widening distally, front margin sinuous, partially 

 serrate, liind margin produced near centre to a strong tooth, distally forming 

 a transverse palm, defined by a tooth with smaller one within; 6*^ Joint 

 shorter, much narrower, projecting finger- wise over palm of 5*^ while the 

 long finger impinges ou middle tooth of 5*^ Gnathopod 2 in Q feeble, 2*^ Joint 

 slightly widened; 5*^ Joint triangulär, broader than the narrowly oval or fusiform 

 6*^, which is without distinct palm. Peraeopods 4 and 5 with 2*^ Joint little 

 expanded, especially that of peraeopod 5. üropod 1, outer ramus much 

 larger than inner, outer margin spinulose. üropod 2 only about half as 

 long as l^t, ramus oblong oval, üropod 3, peduncle rather thick, ramus 

 extremely minute. Telson with 2 dorsal rows of sharp, upturned spinules. 

 Colour pale yellow. L. 9 4, c? 5 mm. 



Inhabita a free menibranous tube, cylindrical, open at both ends, Ist joint of 

 antenna 1 acting as an operculum. 



North-Sea (Northumberland ; Jaederen [Norway], depth 75 — 94 m). 



2. C. sismithi Stebb. 1888 C. s., T. Stebbing in : Rep. Voy. Challenger, v. 29 

 p. 1158 t. 124 I 1893 C. s., A. Della Valle in: F. Fl. Neapel, v. 20 p. 379 t. 55 f. 53—57 | 

 1894 C. s., G. O. Sars, Crust. Norway, v. 1 p. 607. 



