On the Origin of the Organs of Salpa. 123 
black, the third antennal joint less widely and abruptly 
dilated, &c. 
Elasmogaster unicolor, sp. n. 
Pale uniform greyish brown, somewhat coarsely rugulose ; 
antenne with the first, second, and third joints subequal in 
length (fourth joint mutilated) ; membrane almost reaching 
the apex of the abdomen, the lateral margins of which are 
widely dilated ; rostrum almost reaching the anterior coxe. 
Long., ¢ 17; max. lat. abd. 9 millim. 
Hab. East Africa, Nyassa (Cotterell). 
Differing from /. africanus, Dall., the only other described 
species of the genus, by the pale uniform colour, thus strongly 
contrasting in the markings of the body, legs, rostrum and 
‘ antenne, &c. 
Homeocerus Wealet, sp. n. 
Reddish ochraceous, body beneath and legs somewhat 
paler; lateral angles of the pronotum strongly and sub- 
acutely produced ; lateral margins of the abdomen dilated and 
directed upwardly ; antenne with the basal joint longest, 
second joint a little longer than the third or fourth, which are 
subequal in length ; pronotum, scutellum, and corium with 
coarse brown punctures ; extreme lateral edge of the abdomen 
above ochraceous; membrane pale shining brown; rostrum 
with the second joint a little longer than the third and sub- 
equal in length with the fourth joint. 
Long. 14-15; lat. pronot. angl. 5 millim. 
Hab. South Africa (MZ. Weale) ; East Africa, Zanzibar. 
This species appears to find a systematic position between 
the H. dilutus, Stal, and H. productus, Stal. To the first it 
is allied by the dilated abdomen, to the second by the produced 
pronotal angles. 
— 
XXIV.—The Origin of the Organs of Salpa. 
By W. K. Brooks *. 
The Salpa Embryo.—Stated in a word, the most remark- 
able peculiarity of the Salpa embryo is this—It is blocked 
out in follicle cells, which form layers and undergo other 
changes which result in an outline or model of all the general 
* From the ‘Johns Hopkins University Circulars,’ vol. xii. no. 106, 
pp. 98-97. An abstract of Chapter XIV. of ‘A Memoir on the Genus 
Salpa,’ which is now in the press. 
