‘ 676 à General Notes. [July 
cavity ; nor do his statements seem conclusive that they give rise 
to the blood-corpuscles and the fat-bodies. The fact that the 
cells which he finds in the pericardium may originate from the 
entoderm and may form blood-corpuscles is.not so doubtful 
From the somatopleure he derives (1) all the muscles of the body _ 
except those of the mid-gut si elle existe ; (2) the aponeurotic 
layer of the cephalothorax; (3) the membranes of the fore and 
hind guts, of the tracheæ and glands, and of a portion of the 
genital ducts,—that is, of all organs derived from an ectoderm 
invagination ; and (4):the sarcolemma and neurilemma. | From 
the splanchnopleure are developed (1) the envelopes of the mid- 
gut, (2) the genital organs, (3) the pericardium and the pulmo 
nary veins, while the dorsal mesentery gives rise to (1) the heart, 
(2) the lateral arteries, and (3) the suspensors of the heart. 
s will be seen, Schimkewitsch accepts the idea of Bütschli, 
that the cavity of the heart corresponds to the segmentation 
cavity, and that its walls are derived from the two moities of 
the mesentery,—facts which explain the communication of this 
organ with the yelk. The splanchnic mesoderm encroaches | 
upon the yelk, dividing it into lobes, which persist in the lobes 
_ of the liver. The epithelium of the mid-gut begins to form first 
behind, that of the liver being at first formed of two kinds of 
cells, —one representing the true hepatic, the other ferment, cells. 
At the time of hatching no genital openings are developed, but 
the genital glands bend downwards at their anterior extremities, 
and this decurved portion represents the mesodermic portion of 
the genital duct. s 
Of the ectodermal structures we need only to say that the 
with the branchiz of Limulus, our author seems as much at sea 
He 
at first distinct from each other, and from those of the ventral 
m ros o 
mandibular, and maxillary, one pair each, while the pedal ganglia 
