630 PBOP. w. A. heedman's ee vised 



r Colour Srev-greeti, with transparent surface-layer. 

 7 I colour g y g , 1- ^ ^^^^^^^ ^^ ^^ ^^^^^ 



[ Colour not green ^ 



„ r Colour steel-blue ' D.lohatum,G\'ubQ. (Med.) 



"^ I Colour dark grey to black D. fcdlax, Lahille. (Med.) 



The following species cannot be placed : — 

 Trididemnum benda, Delia Valle. (Med.) 

 Bidemnum Grubei, v. Dr. (Med.) 

 B. variolosum, Grube. (Med.) 

 B. roseim (?), Delle Ch. (Med.) 



DiDEMNOiDES, von DrascJie, 1883. 



. Colony thick and fleshy. 



Test containing stellate calcareous spicules, 



Brancldal sac with 4 rows o£ stigmata. 



This genus, or subgenus, contains the following species : — 



r Colour wine-red: spicules numerous B. macroophoruvi*, v. Dr. (Med., 



I [N.W. Eur.) 



Colour resinous yellow-brown ; spicules few. 



B. resinaceum, t. Dr. (Med.) 



1 



Leptoclinum tj Milne-JEdwards, 1841. 



Colony forming a hard, thin, incrusting layer, rarely thick and 

 massive. 



Ascidiozooids with the atrial aperture on or near the anterior 

 end of the body, and provided with a long atrial languet. 



Test very hard and firm, densely crowded with calcareous 

 spicules. 



Brancliial sac usually with four rows of stigmata. 



This genus contains a very large number of so-called species, 

 of which, however, many maybe merely synonyms or varieties, or 

 merely local and seasonal conditions. The descriptions of the 

 majority of these are sc imperfect, that it is impossible to do 

 more than give a list, with an indication of any noteworthy 

 character and of the geographical distribution. 



Leptodinum fulgidicm, M.-Edw. (N.W. Eur., Med.) 

 L. coccineum, v. Dr. (Med.) 

 L. commune, D. Valle. (Med.) 

 L. cinnabarinum, Grube. (Med.) 



* Bidemnum rubellwn, Grube, may be this species, 

 t Including Tetradidemnum of Delia Valle. 



