1907.] FROM THE CAPE VERDE ISLANDS. [49] 



and of the fixed gonopliore, tliis genus lui.s lieen included in tlie 

 family Glavi(l;e, althoiigli the simplicity of the gouophore and the 

 complexity of the branching ahiicst wariant the formation of a 

 new family. 



SoLENIOPSIS DEXDRIPORMIS, .sp. n. ( l^lato XXVI. fig. 1; te.\t- 



figs. 142, 143.) 



The colonies for which this species has been formed weie 

 found at two localities. The solit^rj' colony from Boa Vista is 

 the largest of the series, almost 10 cm. high, with a thick, fn.scicle<l 

 .stem which is, towaids the base, covered by a mass of ramifying 

 tubes, forming a spimgy ti.ssue through which here and there a 

 hj'dranth jirojects. This loosely-built basal ma.s.s attsiins a 

 diameter of 1 cm. From this stem, which in transverse section 

 shows a small central sti'and of chitin with a few minute cojnosarc- 

 containing canals, surrounded by many parallel tubes which again 

 are sui-rounded b}- iriegularly arianged, loose!}" aggreg;ited tul es, 

 the branches arise appro.ximately in one plane. The colonics 

 from St. Vincent are smaller, only 6 cm. high, and la;;k the 

 spong)' basal thickening, possessing a cjdindricnl stem 2 mm. in 

 diameter, composed of closely pncked parallel tubes. Fiom these 

 stems, as from that of the previous specimen, flabeliate bi-anches 

 Ij'ing generally in one plane arise. Tlie primary br;niches bear 

 alternate secondary branches, and these again may Leir tertiary 

 l)ranches, all of these appearing to be fascicled owing to the 

 apposition of several tubes. Single, mouosiphonic branches, how- 

 ever, arise alternatelj' in one plane, for the most part fioai 

 branches of the second and thii'd order, and from the distal end of 

 these the hydrauths project. 



The mode of branching is peculiar. In tlie less strongly 

 fascicled portions of the stem two or thi'ee pei'isiircal tubes lie 

 alongside of, and inseparably united to, one another, e.ach con- 

 taining a strand of coenosarc. Some coiisidondilc distance before 

 a free bianch originates (frequently 20 or 30 mm.) one of th 

 outermost strands divides into two, and round the new ctrnosarca 

 division a chitiuous tube is formed, wedged in between the old 

 tubes. Thus the number of p:uallel-lying and united tubes is 

 increased, but finally, after a course of some 2 or 3 cm., the outer- 

 most of the two portions into which the original strand divided 

 liecomes free to form a branch, and the number of tubes in the 

 farcicle is thus reduced. The ca'nosarc of the free branch divides, 

 as did that of the stem, and becomes en.sheathed in several united 

 tubes which, on bending outwards and becoming free, form new 

 blanches or hydranth-beariug ramuli. The division of the cceno 

 sarcal strands, and consequently the origin of the branches and 

 ramuli, takes place alternately, first on one side, then on the 

 other. 



The hydi-anths project from simjjle, alternate ramuli 0-4 mm. 

 in diameter. Extended they are long and slender, 2'0 mm. by 

 0'2 or 0'3 mm., almo.st cylindricil. with a prominent club-shaped 



Proc. Zool. Soc— 1907, No. XXXIV. 34 



h 495 



