230 



Distribution: The northern tropical Atlantic Ocean between 30° 

 and 37° N and 19° and 42° W, Pacific Ocean in the region of the 

 Philippine and Kuril- Kamchatka trenches; the northernmost report is for 

 45°48' N, 153° 18' E. In the Kuril- Kamchatka Trench a sexually mature 

 female was found in a catch 4,000-5,000 m; all the remaining records 

 from through catches pertain to adult specimens from a depth of 3,000 m 

 and more to the surface and juvenile in catches from 0-1,500 m. 



3. Genus Spinoscina Bowman and Gruner, 1973 



Bowman and Gruner, 1973: 16. — Ctenoscina Wagler, 1926: 430 (part.); 

 Vinogradov, 1957: 219 (part.). 



Pereon somites I and II are fused. Pereon somites II-VII and pleon 

 somites I-III dorsally bear long, narrow, recurved denticles which are 

 deeply denticulate on the anterior margin; urosomite I has a small dorsal 

 denticle. The head has two lateral and one median forwardly directed 

 long spines. The eyes are not discernible. Antennae I exceed the length 

 of the pereon. Antennae II in females are completely reduced. Maxil- 

 lae I have a better developed one-segmented palp, and armed outer and 

 rounded inner lobes. The lobes of maxillae II are separated. The maxil- 

 lipeds have oval outer lobes and comparatively large inner lobes which 

 may reach half the length of the outer. Coxal plates VI and VII are fused 

 with the pereon somites. The pereopods are unusually long and thin. 

 Pereopods I have chelae, as in Ctenoscina. The 2nd segment of pere- 

 opods V is armed with thin spines. The claws of pereopods III-VII are 

 very small, curved, but not retractile. Pereopods VII are slightly shorter 

 than pereopods VI. The telson is fused with urosomite III. The gills are 

 located on pereon somites III-VI. 



Type species: Acanthoscina spinosa Chevreux, 1914. 



Chevreux (1914) described a new species of the genus Acanthos- 

 cina — A. spinosa — based on several features differing significantly from 

 those in the other species of the genus, A. acanthodes. Later, Wagler 

 (1926), having no personal material of this species and relying solely 

 on Chevreux' s description, transferred A. spinosa to the genus Ctenoscina 

 newly established by him. However, Chevreux gave only a very brief 

 description of the crustacean, in which the structure of the mouthparts 

 was not included. A more thorough examination of the other specimens of 

 the same species by Vinogradov (1957) showed that C. spinosa differs 

 in several significant characters from the other species of the genus 

 Ctenoscina (see description of the genus). Later, one more species was 

 192 identified, which is close to C. spinosa. Thereby the genus Ctenoscina, in 

 the volume accepted by Wagler, became divided into two mutually sharply 

 differing groups of species, which provided the basis on which Bowman 

 and Gruner (1973) separated the independent genus Spinoscina. 



