47 
TRANSLATIONS, 
On the DeveLopMENT of Sacirta. 
By Dr. C. Grcrnsavr. 
(‘ Abhandl. d. Naturf. Gesellsch. in Halle,’ 1857.) 
Havine in a former volume of this journal given an ac- 
count of what is known respecting the structure and relations 
of Sagitta bipunctata, we have thought that an abstract of 
Dr. Gegenbaur’s observations on the subject of reproduction 
in that genus would not be unacceptable; and the more so, 
as this part of the history of Sagitta has hitherto been in- 
volved in much obscurity. 
In the sea at Messina three distinct species of Sagitta 
came under the author’s observation. S. bipunctata, which 
he appears not unfrequently to have met with of the large 
size of 2” 2’ in length, and two other forms which he was 
unable to refer to any known species. One of these, 9!” long, 
was of slender shape, attenuated for some distance beyond 
the head, and again, beyond the middle of the body, tapering 
off suddenly to the caudal extremity, had two pairs of lateral 
and one caudal fin; the former rounded and projecting but 
little, whilst the caudal fin was very broad. The surface of 
the body, moreover, was studded with warty tubercles, occa- 
sionally disposed with perfect symmetry and supporting 
bundles of fine sete. The head triangular, somewhat 
acuminate in front. The other species was less common, 
the largest individuals not more than 6’ in length, the body 
almost cylindrical, very slightly constricted behind the rather 
broad head, and truncated at the caudal extremity; the 
whole surface of the body was covered with very numerous 
bundles of set (0:08 in length), which gave it an almost 
villous aspect. The anterior lateral fins, very long and nar- 
row, commenced at the end of the first quarter of the length, 
terminating in a projecting point about the middle of the 
body. The posterior pair, wider in proportion, had a strongly 
curved border. The caudal fin was abruptly rounded oft. 
Both species were transparent, and had, like all their con- 
geners, two brown pigment-spots behind the opening of the 
vasa deferentia. No important distinction could be drawn 
