BRIGGS. 1 49 



GONOSOME OF LICTORELLA CONCINNA.— The gonangia are attached 

 m a dense cluster to the main stem forming a coppinia mass which surrounds it 

 on all sides. The great majority of the gonangia stand out at right angles from 

 the stem ; a few, however, are more or less closely appressed to its surface. 

 This mass of aggregated gonangia occupies a length of 3.5 mm., on the main 

 stem and comprises some ninety individual gonothccae. The gonangia are ovate 

 with undulated edges, truncated at the distal end, and tapering towards the 

 proximal extremity. They usually pass into the very short peduncle gradually 

 and without any distinct constriction or interruption. In frontal aspect each 

 gonangium is a little narrowed in near the distal end and then widens outwards 

 forming a conspicuous round projection or shoulder at each side of the top where 

 the gonangium reaches its maximum width. These shoulders are produced 

 slightly downwards into truncated processes, each of which ends in a small cir- 

 cular aperture directly facing towards the proximal extremity of the gonangium. 

 . The summit of the gonangium is usually convex, although in a few examples it 

 may he slightly concave between the rounded shoulders. The gonangia attain 

 a length of 0.77 mm., with a maximum width, in frontal aspect, of 0.33 mm., 

 at the distal extremity. When viewed laterally the profile is obovate, and the 

 gonangium reaches a maximum width of 0.28 mm., about two-thirds of the 

 length of the body from the proximal end. 



Ritchie has already drawn attention to the striking resemblance between 

 the trophosome of Lictorella concinnu and that of Lictorella cervicornis , Nutting 

 1= Zygophylax cervicornis) from the Hawaiian Islands (6). Nutting's species, 

 however, differs from L. concinna in that there is a nematophore at the base 

 of each pedicle. There was no trace of these structures in the "Thetis" speci- 

 mens, nor do they occur in the more abundant material which I now have at my 

 disposal from a few miles south of the type locality. Although Ritchie con- 

 sidered the absence of nematophores in L. concinna significant, he was uncertain 

 whether their presence or absence fell within the range of everyday variation, 

 but the totally distinct gonosomes possessed by Zygophylax cervicornis and 

 Lictorella concinna establish at once the validity of his species. 



According to Nutting's description the gonosome of Zygophylax cervicornis 

 has the following structure: — 



"GONOSOME. — Gonangia forming a "Coppinia" mass on the main stem, 

 roughly triangular in outline, the distal ends being the broader on account of 

 the opposite shoulders, which are quite conspicuous and end in round apertures. 

 Midway between these shoulders there is a short neck ending in <a third aperture. 

 The individual gonangia are borne on short branchlets, which continue beyond 

 them, arching over each gonangium so as to form a protecting network of such 

 branches over the aggregated gonangia." 



Although L. concinna closely approaches Lafoea convallaria, Allman (1), the 

 differences in the characters of the trophosomes are well-marked and the gonangia 

 are quite distinct. Clarke (5) describes the gonangia of L. convallaria as 

 "sessile and. anchor-shaped, with the orifices, of which there are two in each 

 gonangium, at the extremities of the obtusely pointed flukes." 



II.^NOTES ON NOMENCLATURE. 



During the course of preparation of a catalogue of the Hydroid Zoophytes 

 of the coast of New South Wales certain changes in the nomenclature have been 

 found unavoidable and it has been necessary to propose new names for three 

 species. The reasons for such changes will be found under the species affected. 



