278 PROF. ALLMAN ON NEW GENERA 



carries usually two hydrothecse at the proximal side of the gonan- 

 gium, and at its distal side is reduced to a short blunt spine 

 destitute of hydrothecse ; gonangia oval, greatly compressed, 

 concave on one side and convex on the other, with a transparent 

 wmg-like margin ; sporosac encircled near its summit by a band 

 of refringent roundish corpuscles. 



Locality. Ceylon, Mr. Soldsworth. 



This is a loosely branched straggling species ; the peculiar form 

 of the hydrothecEe, with the deep iufiexion below the margin, 

 somewhat resembles that of a sac constricted by a cord below its 

 mouth, and bas suggested the specific name. 



The remarkable band by which the solitary sporosac which 

 occupies the gonangium is encircled, is composed of highly re- 

 fringent spherical corpuscles, which by mutual pressure have 

 become more or less polygonal. They possess a central nucleus- 

 like body, which, when the gonangia are subjected to a short 

 boiling in a solution of caustic potash, becomes resolved into a 

 -cluster of granules. It is impossible to form any valid conclu- 

 sion as to the significance of these bodies ; they are certainly 

 not ova. 



The gonangium is solitary, and is borne on a shortened hydro- 

 thecal pinna whose proximate two hydrothecse present the normal 

 condition, while the third hydrotheca is replaced by the gonan- 

 gium, its mesial and lateral nematophores continuing, with but 

 slight arrest, to occupy their usual position, so that the mesial 

 nematophore is placed in front of the gonangium, wbere it re- 

 mains free, and the lateral nematophores one on each side of it 

 and distally. That portion of the pinna which lies at the distal 

 side of the gonangium has become arrested and reduced to the 

 condition of a thick blunt spine. 



Were it not for the much less modified condition of the pinna 

 which carries the gonangium, the present species would form a 

 typical example of Dr. Kirchenpauer's macrorynchial section of 

 Aglaophenia. 



Halicornaria insignis. Plate XXIII. fig. 1, and Plate XXII. 

 figs. 3, 4. 



Tropliosome. Hydrocaulus attaining a height of 9 inches, simple, 

 monosiphonic, closely set with opposite pinnge. Hydrothecse with 

 a very long recurved and strongly divergent tooth on each side, 

 intrathecal ridge strong, extending from about the middle point 



