518 REVISION OF THE AXINELLID^, ii., 



Megascleres of a single order : tylostyli, subtylostyli, or tylo- 

 strongyla, occasionally in part reduced to styli. Microscleres: 

 sigmata and (or; toxa, the latter sometimes in dragmata. 

 Type-species. — T. inornata Bowerbank. 



In proposing the name I'yJodesma, in lieu of Desmacella, for 

 the genus wrongly designated Biemiia (misspelt Biemma) by 

 Topsent(46), Thiele(41) omitted to indicate which species was to 

 be considered the type : since, however, two species only (other 

 than those described by him as new) were enumerated by Topsent 

 as belonging to Bietnna, — viz., B. inornata Bowerbank, and B. 

 corrugata Bowerbank, — it is one of those, no doubt, which should 

 be preferred, and I select the former, both because it is that 

 which was named first in order by Topsent and is the better 

 known. The name Tylodesyna is adopted here in preference to 

 Des))iacella, nut so much from conviction of the correctness of 

 Thieles contention accepted by Wilson(61) and some other 

 authors, but not by Dendy(8) — that the latter name is properly 

 a svnonym of llamacantha, as owing to the fact that the original 

 species of Desmacella described by Schmidt— viz., D vayahunda 

 and D. p«mi/!to are imperfectly known, and may possibly 

 prove not to belong to the present genus 



For reasons already stated above in my remarks on Biemnn, a 

 slightly amended definition of Tylodenma is here proposed, 

 necessitating the removal therefrom, to the former genus, of 

 Hentschel's Tylodesma niicroslroiigyld and T. 7nic7'ocfa, and the 

 addition thereto oi Bienina hu7nilis Thie\e, B. tvitncata Hentschel, 

 and B. vulgaris Topsent. 



Leaving out of account Topsent's Biem-iia daufzeiibergi and 

 B. chevreuxi, the former of which is stated by Lundbeck(30) to 

 be identical with T. rosea Fristedt, and the latter by Topsent(53) 

 himself to be identical with T. atinexa Schmidt, the species 

 which 1 regard (provisionally) as belonging to Tylode ma are as 

 follows : — 



T. inornata Bowerbank(l); (46); (53). Shetland Is.; Azores. 



T. corrugata Bowerbank(l); (46). British Is.; Azores. 



T. annexa Schmidt(36); (30). North Atlantic; widely 



distributed. 



