AND OTHER MEDITERRANSAIir LOCALITIES. 1^- 



some specimens being entirely without while others have it to 

 some zocecia. This " additional spine " is found quite as fre- 

 quently in the Mediterranean Bugula calathus as in B. ditruvce. 

 Some specimens have to some zocecia three outside spines and two- 

 inside, while other zocecia have three outside and three inside. 



The primary zooecium has a central spine at the base of the 

 area, flanked by a spine on each side, and at the top of the area^ 

 a pair of spines at each corner, and in more than one specimen 

 this primary zooecium has an avicularium ; and this is the only 

 species in which 1 have seen avicularia to the primary cells. 



The beginning of the colony grows up straight at first, then 

 dichotomizing from a centre forms a cup. 



This is in most respects nqv^ similar to B. spicata, H., which 

 1 have biserial from Naples and Capri, while from JN'aples and 

 Trieste it is 4-serial, and in these the outer avicularia are ]ar<^er 

 than the inner. The avicularia of B. spicata and B. turhinata 

 are almost identical in shape. 



The B. ditrupcB in my collection from Naples and Capri are 

 biserial, while those from Trieste are 4-serial, and in these again 

 the outer avicularia are larger than the inner. 



A specimen from Eapallo, having been decalcified, does not 

 admit of complete comparison. 



Bugula calathus, Norman. (PL 2. figs. 4 & 10.) 



Bugula calathus, Norman, Q. J. Micro. 8c. (n. s.) vol. viii. p. 218, pi. vi. 

 figs. 3-8; HincH, Brit. Mar. Polyzoa, p. 82, pi. xi. figs. 4-6; id. Ann. 

 Sf Mag. Nat. Hist. ser. 5, vol. xvii. p. 260. 



Bugula avicularia, forma flabellata. Waters, Ann. Sf Mag. Nat. Hist. 

 ser. 5, vol. iii. p. 1 17- 



It has been considered by Pergens and others that the 

 Mediterranean form should be called Bugula calathus ; and 

 although I. should not have been prepared myself to separate it 

 from B. jlahellata, yet in deference to the opinion of others I 

 leave it as B. calathus, instead of considering it the Mediter- 

 ranean form oi flabellata. The cells, ovicells, and avicularia are 

 smaller than those oi B. flabellata from Roscoff; whereas Hincks 

 says of the British B. calathus that these organs are on a larger 

 scale than in B. flabellata. The mandible in B. flabellata is 0"lt> 

 mm. long, and in the Mediterranean B. calathus 0'12 mm. The 

 character chiefly relied upon for the separation of the tv\o 

 species is the contrast in colour ; but Yigelius (" Ontogenie der 

 Marinen Bryozoen," Milth. a. d. Zool. Stat. z. Neapel, vol. vi^ 



