%vith Observations on Australian Hydroids. 107 



Sertularia ahietina and 8. filicida are the t3q:>es, which 

 group the author proposes to separate as a distinct genus 

 under the name of Abietinaria. There appear, however, to 

 be no very definite grounds for this distinction, and on 

 equally good foundations the genus Sertularia might be 

 divided into fully half-a-clozen genera. 



Among the species of Thuiaria and Sertularella a number 

 from Australia are mentioned, several of which are described 

 as new. I subjoin a few notes regarding some of them. 



Thiiiaria lichenastruni, Pallas, sp. — A form which occurs 

 in a number of widely-separated localities, inchiding Aus- 

 tralia and Kamschatka, is referred to the above species by 

 Kirchenpauer, who considers it perhaps synonymous with 

 Busk's Sertularia crisioides (but not with the Dynamena 

 crisioides of Lamouroux.) Busk's species, however (which I 

 have described in the " Catalogue" under the name of 

 T. fenestrata), is not the same as the present form, from 

 which it may be readily distinguished by the vertical 

 apertures of the hydrothecse, and the four-toothed margin of 

 the gonangium. 



Thuiaria cartilaginea, K. — This species seems to resemble 

 T. lata in some respects, but is peculiar in the absence of 

 hydrothecge from the stem and branches. 



Sertularella reticulata, K. — A tricuspidate species from 

 Bass' Straits, differing from 8. Johnstoni in being incon- 

 spicuously toothed, and in the peculiar habit. It is dicho- 

 tomously branched, with the branches all in the same plane, 

 and often anastomosing, so as to form a net. 



Sertularella suh-dicliotoma, K. — A species from Bass' 

 Straits and Mas^ellan's Straits, described as differino^ from 

 S. Johnstoni in its habit, which is not pinnate, but iri-e- 

 gularly dichotomous. Busk's S. divaricata comes from the 

 same localities as the above, but, though rather straggling, 

 it is distinctly pinnate, and cannot therefore be identical 

 with this species if Kirchenpauer's description is accurate. 



Sertidarella infracta,K. — Tliis species, of which no figure 

 is given, is said to diff"er from S. Johnstoni chiefly in its 

 strong and robust habit, and in the form of the gonothecse, 

 which are '' pear-shaped, short, thick, strongly inflated, and 

 deeply ringed." The hydrothec?e are bent outward about 

 the middle of their length. This feature, however, is not at 

 all uncommon in S. Johnstoni and S. divaricata, the latter 

 of which answers well to the description of >S^. infracta, and 

 is very likely identical with it. 



