328 LANGENBECK. [VoOL. XIV. 
over the whole dorsal region of the abdomen. The blastopore, 
evidently, is carried over the posterior pole of the egg, and 
finally lies at or near the extreme tip of the abdomen (¢f. Figs. 
36-43). In consequence, the proctodaeum, which invaginates 
just posterior to the last appendage, forms either in the blasto- 
poric area or just anterior to it, as is the case in the decapods. 
In the decapods, however, the stomodaeal and _ proctodaeal 
invaginations form the greater part of the intestine, while 
in the amphipods both stomodaeum and proctodaeum are 
very short. Figs. 59-64 represent sections of an embryo of 
the fourth day cut parallel to the line +r (Pl. XXVII, Fig. 44). 
Owing to the folding of the embryo, the sections pass through 
stomodaeum and proctodaeum, cutting them transversely, while 
the dorsal sections cut the digestive tube horizontally. In 
Fig. 59 we see both stomodaeum and proctodaeum. The cells 
are closely packed and columnar. In the next section (Fig. 
60) the stomodaeum is still seen as a round tube, but the proc- 
todaeum has broken through. Another section showed that 
the stomodaeum has also broken through. On examining Fig. 
61 it will be seen that the part of the digestive tract immedi- 
ately adjoining the stomodaeum and proctodaeum is not formed 
at this time. Six large nuclei are seen bordering the yolk 
area in the thoracic region, whereas only three long, spindle- 
shaped cells could be seen bordering the yolk of the abdominal 
region. Two sections beyond this (Fig. 62) show the anterior 
ends of the liver tubes. The cells have large vacuoles, and 
inclose the whole yolk area. In the next section (Fig. 63) the 
liver tubes are pushed somewhat apart, and the irregular mass 
of cells between them represents the digestive tract just begin- 
ning to form in this region. In Fig. 64, where the section 
passes through the dorsal organ, the digestive tract is com- 
pletely formed of large, vacuolated cells, with large, clear 
nuclei looking exactly like those of the liver tubes. Another 
section shows the digestive tract shading off into the large 
yolk areas of the thoracic and abdominal regions. All the 
yolk in these sections is inclosed in the liver tubes and the 
digestive tract. I have never seen any outside of them being 
digested by special vitellophags as Dr. Pereyaslawzewa ('88) 
