84 
F. ERNEST WEISS. 
HistioteutLiis. In connection with this ridge, probably along 
its base, as being there protected, will be found the sensitive 
epithelium. In Ommastrephes the ridge in the ventral facet 
is very small, and seems to be partly iutroverted into the skin. 
Here I found a sensitive, or at least a highly modified, epithe- 
lium, which I will describe later on. 
The nuchal cartilage is more elevated and narrower than in 
Chiroteuthis, and more of the Ommastrephes type. 
The depressions at the base of the siphon are elongate, 
broader aborally, and tending to separate into two fossae. The 
cartilage on the mantle wall is elongate, pear-shaped, and less 
definite and prominent aborally (PI. X, fig. 11). 
The siphon is provided with a strong muscular valve, as 
has been already stated by Professor Lankester (PI. X, fig. 10). 
The gills are very powerfully developed. Two strong mus- 
cular renal papillae are situated somewhat anteriorly to the base 
of the gills and on either side of the rectum (PI. X, fig. 11). 
Two large nidimental glands, on the same level as the 
base of gills, but median to them, project freely into the 
mantle cavity (PI. X, fig. 11). 
Two oviducts, with terminal glands, open dorsad of the gills 
between their base and the renal papillae. At the end of the 
oviducal gland proper ( gl .) there is a further glandular struc- 
ture, corresponding minutely in structure with the nidimental 
gland, but about twice the size, and, indeed, almost as large as 
the remainder of the oviduct. The external opening of the 
oviduct extends about halfway along this gland. The oviducts 
correspond so closely with those of Thysanoteuthis rhom- 
bus, figured by Brock, 1 that they might stand as a drawing of 
those of Histioteuthis. The internal openings are slit-like and 
situated near the lower end of the coelomic cavity, thus differ- 
ing from the oviducts of Chiroteuthis, which are short, and open 
far up into the ccelom. The beginning of the oviduct shows a 
glandular passage. 
On opening the renal chamber it is found to be compara- 
tively long, containing the vena cava and renal veins, with 
1 Brock, ‘ Zeitschrift f. wiss. Zoologie,” 1882. 
