246 
present. The youngest of them (Fig. 12 a) has already a well devel- 
oped skeleton, which is very characteristic, and strikingly contrasts 
with the corresponding stages of hitherto investigated Scalpellum 
in having only one pair of peduncular scales 
developed before the lower latera appear. 
On the other hånd, these first scales of the 
peduncle are much larger in the young than 
any plate of the capitulum. In the capitulum 
carina, terga, scuta, and upper latera are 
already present in the smallest specimen; 
the chitinal, primordial valves are extra- 
Fig. 12. Scaipeiiopsis trio,o- ordinarily small. The shape of the young 
ciiiata , off Joio. a. younger jndividual is very characteristic already in 
specimen in carinal view; enOfmOUS develop- 
in lateral aspect. [x 52]. ment of the dorsally situated first pair of 
peduncular scales \ in dorsal aspect the basal breadth measures 
about one third of the length of the animal. On the ventral side 
the characteristic broad furrow of the peduncle is already strongly 
indicated. The all but quadrangular shape of the first pair of ped¬ 
uncle scales strikingly differs from the ribbonlike scales of the 
adult. But the aspect of the small specimen is already so charact¬ 
eristic that it is easily identified. 
a. 
b. 
Genus Protomitella nov. 
Capitulum plates numerous, of two different kinds. Carina, 
terga, scuta, and rostrum well developed, often also upper latus, 
and a subcarina. The lower latera long and narrow, very numer¬ 
ous. Skeleton of the peduncle small, crowded spines. — Males 
with carina, terga, scuta, and rostrum; accessory plates may occur. 
This curious genus links together the genera Calantica , Mi- 
tella, and Lithotrya. The males attain the same high development 
as in Calantica; in one case I even found one latus indicated. 
The irregular, and numerous small, lower latera in the hermaphro- 
dite in regularly shaped specimens recall those of some Mitella- 
species to confusion, and the possibility cannot be denied that the 
species described below may turn out to be synonymous with Pol- 
