THE COLLECTIO]Sr OF MISS H. GATTT. 143 



The heiglit of the trophosome in the present species does not 

 exceed -j^ of an inch. The enormous size of the gonangia as 

 compared with the minuteness of the trophosome constitutes a 

 striking feature in this diminutive Sertularia. The height of the 

 gonangium, exclusive of the peduncle, exceeds the combined 

 length of three internodes of the stem, which here resembles a 

 mere appendage to the gonangium, instead of being, as is usually 

 the case, the most voluminous portion of the colony. Only 

 one gonangium is borne by each stem, and this always springs 

 from the proximal hydrotheca-bearing internode just above the 

 peduncle by which the stem is attached to the creeping stolon. 



Sertularia r)iegalocarpa is nearly allied to S. humilis, whose 

 large gonangia are quite similar in form and origin to those of 

 the present species. In the narrower hydrothecse, however, of 

 8. onegalocarpa and their greater freedom from the supporting 

 internode, a distinction of specific value will be found. 



Desmoscyphus. 



Desmosctphus oeieisstis, n. sp. (PI. XVII. figs. 1-4.) 



Trofliosome. — Hydrocaulus irregularly branched, set with 

 alternate pinnae ; internodes of pinnse separated by oblique joints, 

 each internode carrying near its middle one, or occasionally two, 

 pairs of hydrothecse. Hydrothecse abruptly swollen at the base, 

 where those of each pair are confluent with one another, then 

 tapering to the distal end ; aperture deeply cloven. 



Gonosome. — Gronangia borne by the main stem, pyriform, with 

 the aperture terminal, wide, and scarcely raised above the surface 

 of the gonangium. 



Locality. Bass's Straits. 



This is a very striking form. The hydrothecse of each pair are 

 closely adnate to one another by their swollen bases, while their 

 distal tapering portions, though diverging to the right and left, 

 are all turned to one side. They thus present a unilateral or 

 secund aspect when viewed in profile, while in a front view they 

 appear to be directed to the right and left. The deejDly cleft 

 orifice of the hydrotheca is very striking and characteristic. In 

 most cases but a single pair of hydrothecse is borne on each inter- 

 node ; but occasionally the internode becomes more elongated 

 and carries two. The species comes near to Sertularia geminata, 

 Bale, from which it is distinguished by the swollen bases of the 

 hydrothecse. 



The specimen consisted of a piece of about 2 inches long. 



