1890.] Zoölogy. 681 
vitellophags. They metabolize the yolk which is contained in each, 
but the cells themselves are directly converted into the lining epithe- 
lium of the mid gut. By this process a lumen is formed, first at the 
anterior end. The stomodeal-mesenteric wall is first to break through ; 
the opening into the proctodeum appears much later. The procto- 
deum is very short, not extending far from the anus. 
(8) In embryos at the time of hatching the sternal artery has arrived 
at the condition found in the adult scorpion. It consists of a tube 
lying on the upper surface of each half of the cesophageal nerve ring. 
Not until much later than my studies have gone does it attain the in- 
vesting character of the adult. 
(9) Packard's ** brick-red gland ” is of mesodermal origin, It con- 
tains in its interior the cavity of the fifth post-oral somite. Its inner 
end is terminated by a thin layer of flattened epithelium. It soon be- 
comes folded on itself, and the region of the bend grows rapidly for- 
ward. The outer limb of the fold becomes in turn folded at four points, 
and these new bends grow out in each body segment, giving rise to the 
lobes characteristic of the organ in the adult. With the folding 
numerous fusions of the walls occur, followed by perforations, giving 
rise to the peculiar anastomosing structure of the adult organ. 
These points, so briefly summarized, go far, I think, toward the sup- 
port of that view which would recognize a close relationship between 
Arachnids and Limulus, while at the same time they serve to remove 
the Merostomata more widely from the Crustacea,—]. S. KINGSLEY, 
July 17, 1890. 
A Review of Some ofthe North American Ground Squir- 
rels of the Genus Tamais.—By J. A. Allen. —Bull. Am. Mus. Nat. 
Hist., Vol. III.—This paper is a revision of the ** Zamais asiaticus 
group of a former monograph of the genus Tamias, made necessary by 
the accumulation of a variety and quantity of new material during the 
last five years. It is a valuable contribution to mammalian literature. 
The material in hand seems to require the provisional recognition of 
not less than twenty-four forms, of which thirteen are here for the first 
time described. These twenty-four forms fall into several more or less 
well-marked groups, as follows : 
1. The Aindsii group, consisting of (1) T. hindsii, (2) T. townsendii, 
(4) x. ee (4) T. senex, (5) T. quadrimaculatus, (6) T. 
merriamii. 
2. The dorsalis group, consisting of (1) T. dorsalis, (2) T. obscurus. 
3. The zmdrinus group, consisting of (1) 7. umórimus, (4) Z7. 
cimereicollis, (3) T. bulleri. 
