PAVE, Vila: 
a. Anus. i n. Nerve ganglion. 
ab. Abdomen. oc. Eye, 
br. Gills. ocl. Ocellus. 
cp. Carapace. pp. Protoplasm. 
et. Cuticle, larval skin. r. Rostrum 
dp. Deutoplasm. a Contour of body 
J. Frontal sense-organ. B. Larval skin. 
i. Intestine. y-  Chorion. 
l. Liver. € Place of attachment of branchial apparatus. 
76. Labrum. ¢. Abdominal muscles. 
mt. Metastoma. A. Dorsal organ. 
The Roman numerals denote the appendages of the body in their consecutive order 
1-4. Development of Stomatopopa, continued. Figures from W. K. Brooks and 
Watter Faxon. 
1. Larva of Squilla empusa, older than the one represented on Plate VII. fig. 19. Ventral view. The anten- 
nulary segment has become marked off at the anterior end of the body, and the third flagellum of the adult 
antennule is present. The second antenna has a rudimentary three-jointed inner branch or flagellum. The 
six posterior thoracic appendages have acquired essentially their permanent form. The sixth abdominal 
somite has become free and bears a pair of large swimmerets (XIX) similar in form to those of the adult. 
The abdominal appendages of the left side are omitted in the figure. From Brooks, Ibid., Pl. X1. 
2. Still older stage of the same, dorsal view. Length 17 mm. The abdominal appendages are not shown in the 
figure, excepting the last pair (XIX). From a sketch by Faxon, made at Newport, R. 1., August 24, 1876. 
3. The specimen represented in fig. 2, moulted on the 25th of August, assuming the form shown in fig. 3, 
from the lower side. It is now 19 mm. long, and has the characters of the adult Squilla empusa. All 
the abdominal limbs are present, but are omitted in the figure with the exception of the last pair (XIX) and 
the right one of the first pair. From a sketch by Faxon. 
4. Part of the border of the telson of the same, more highly magnified. 
ns) 
5-8. Development of Cumacnsa. Figures from Anton Dourn, Untersuchungen tiber Bau 
und Entwickelung der Arthropoden. 1. Ueber den Bau und die Entwickelung der 
Cumaceen. Jenaische Zeitschr., V., Taf. II., 1870. 
5. Early stage in the development of the embryo of Cuma Goodsiri. a, contour of the body. 8, larval skin. 
7, chorion. A, dorsal organ. Behind the dorsal organ a deep fold gives the embryo a marked dorsal 
flexure. Through this dorsal flexure and dorsal organ the embryo exhibits a striking resemblance to the 
embryo of Isopods. Cf. Plate VI. The sixth pair of appendages, however, unlike the corresponding pair 
in the Isopod embryo, at this early stage is two-lobed and resembles the six following pairs of appendages. 
Rudiments of all the appendages are present from the first to the twelfth. cp, carapace commencing as a 
fold in the region of the maxille. 7, liver. 
6. Later stage of the same. The outer membrane has been cast off. The caudal appendages (XIX) are present. 
7. Later stage. The embryo now approaches the Decapod type. The larval skin has been shed, the dorsal organ 
has disappeared, and the dorsal flexure is exchanged for aventral one. The bulk of the first maxilliped (V1) 
is formed from the exopodite while the similar second maxilliped (VII) represents the endopodite alone, 
the external branch having entirely disappeared. X’, XT’, rudimentary exopodites of the tenth and eleventh 
pairs of appendages, The twelfth pair is now devoid of external branch. 
8. Larva ready to leave the brood-sac. , place of attachment of the branchial apparatus. The last pair of 
thoracic legs has not yet developed, nor the appendages of the abdomen except the last pair (XIX). The 
abdominal appendages are never developed in the female. The eyes, which are not shown in the figures, 
are developed on each side of the head, and coalesce at a later period to form the median sessile eye of the 
adult. : 
