185 



ding, open, curved line. Nothing can be said with regard to the dimensions of 

 the spicules, the small fragments examined having no doubt lost most of these 

 structures, of which only a few curves were left. 



A few, very broad ooecia were found, showing a striation starting from the 

 central suture. The operculum of the gonozooecium has two frontally convergent 

 but not concurrent chitinous sclerites. 



Of this form I have been able to examine some laminate fragments from 

 California (Hindi's Collection), belonging to the Museum of Zoology at Cam- 

 bridge. 



Thalamoporella novae hollandiae Haswell. 



Vincularia novae hollandiae Haswell, Proceed. Linnsean Soc. of New South Wales, 



Vol. V, Part I, 1880, p. 41, PL III, fig. 3. 



(PI, VI a, figs. 3 a-3 f). 



The zooecia, whose lateral margins are often more or less sharply angularly 

 bent, are 0,066— O.OTg"""- long. The length of the large wide aperture, which 

 has a broad and deep sinus, may be contained 272—3 times in the whole length 

 of the zooecium, and the adoral areas, always without spines, are much reduced 

 or quite absent. The operculum has only in the older zooecia a continuous, but 

 extremely narrow proximal sclerite. As a rule only one of the two opesiular out- 

 growths reaches the basal wall, which it meets in a somewhat variable, but most 

 often irregularly tongue-shaped, closed curved line, pointing obliquely towards 

 the proximal end; one leg of the line may sometimes join the distal wall. The 

 other may however also — in some cases in about half of the zooecia — reach 

 the latter in a much smaller, but also closed curved line. The cryptocyst is very 

 tuberculous, surrounded by strongly developed, irregularly crenulated prominent 

 margins and furnished with numerous, rather large pores. The polypide-tube is 

 short and its frontal wall not much depressed. 



Spicules. Only compasses occur, varying in length, between 0,066 and 0,505*"™-, 

 as also in respect to the angular bending of the legs. In the smaller of them, 

 which are also found between the cryptocyst and the covering membrane, the 

 angle varies between 98" and 110"; but there is no definite limit between these 

 and the longest, which are very slightly curved, and the size of the angle seems 

 to increase according to the length. 



Ooecia are not found. 



The avicularia, which may attain about the size of the smaller zooecia, are 

 furnished with a strongly developed and deeply depressed cryptocyst. The man- 

 dible, the proxinial part of which i§ contract^dj has otherwise the form of a 



