386 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
two breeding periods in summer ; the gonads lie on each side of the gut 
on the walls of the body-cavity ; the eggs pass into the operculum, where 
they are fertilised ; the operculum does not, however, serve as a brood- 
pouch, as in Sp. spirillum ; the encapsuled eggs lie in a long mem- 
branous sac along the mid-dorsal furrow. The eggs are telolecithal, 
with considerable nutritive yolk. The blastula has a small blastocoele ; 
a gastrula is formed by invagination. Nine larval stages are described, 
which follow one another in rapid and direct succession in the three days 
between the first segmentation and the emergence of the free-swimming 
ciliated form. 
Septal Valves of Owenia.* * * § — Prof. G. Gilson continues his study of 
Oivenia. (1) The perivisceral compartments are less numerous than the 
metameres; details of the relation are given. (2) The septa are not 
complete ; some show gaps at their attachment to the body-wall, others 
have perforations, others have holes surrounded by a muscular sphincter. 
Several septa have both marginal gaps and sphinctered apertures. (3) 
The coelomic cavity of certain metameres is in communication with the 
exterior. The sixth shows in the female a ciliated funnel applied to 
the third septum, and provided with a short canal which perforates the 
wall and enters an epithelial sinuous tube lodged in the epidermis. In 
the male there are two pairs. In both cases they are genital. At the level 
of septa v. and vii. there are two epidermic invaginations in the ^thick- 
ness of the septa ; each ends at the sphincter, and perhaps opens into the 
body- cavity. Less developed structures occur in most of the septa. (4) 
The genital funnels arc probably modified nephridia. The epithelial 
tubes may have the same significance. Perhaps the septal canals and 
Ihe sphincters may be vestiges of nephrostomes. The secretory function 
of the true nephridia has totally disappeared. 
New Species of Perichaeta.f — Dr. W. B. Benham describes and gives 
diagnoses of five new species — Perichseta novse britannicse, P. Sedgiciclcii, 
P. Arluri, P. Floweri, and P. Madelinse. The first three are from New 
Britain, the other two from Singapore and Borneo respectively. He also 
describes P. malamaniensis, which he named in 1891. At the end of his 
paper, Benham offers some remarks on Michaelsen’s criticism of the value 
of certain specific characters of the genus. 
New Species of Earthworm.^ — Dr. W. Michaelsen describes three 
new species obtained from the Hamburg Botanic Garden, but really 
belonging to the West Indies and South America, viz. Tykonus pere- 
grinus, T. wiengreeni, Criodrilus breymanni. 
Chaetognatha of Misaki.§ — Mr. T. Aida gives a list, with descrip- 
tive notes, of twelve species of Chastognatha which he collected in Misaki 
harbour. He follows the classification of Langerhans, and describes four 
of the forms he found as new, viz. Sagitta neglecta , a very small form 
* La Cellule, xii. (1897) pp. 377-416 (3 pis). 
t Journ. Linn. Soc. (Zoo!.), xxvi. (1897) pp. 198-225 (2 pis. and 4 figs.). 
X Zool. Jalirb. (Abth. Anat.), x. (1897) pp. 359-88 (1 pi.). 
§ Annot. Zool. J&pon., i. (1897) pp. 13-21 (1 pi. and 1 fig.). 
