528 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Lamellibranch with an Internal Shell.* — M. Felix Bernard de- 
scribes Ghlamydoconcha Orcutti , found by Orcutt in 1882 near San 
Diego (California), and first described by Dali in 1884. It has an 
extremely reduced internal shell and no trace of adductor muscles. 
The shell is lodged in the thickness of a delicate pallial lobe, which 
is itself covered by a thicker fold with abundant sensitive papilla} and 
glands. An anterior dorsal aperture allows the water to enter between 
the lobes. The mantle shows an anterior projecting lobe, a ventral gap 
for the foot, and a short anal siphon. Internally the animal is not at 
all divergent. Apart from mantle and shell, it seems like a Eulamelli- 
branch of median specialisation, near the Carditidae, especially those 
of the group Erycinacea, such as Bornia. The author also compares 
Clilamydoconcha with the yet more divergent Scioberetia. 
Siphonal Papillae of Cockle.!— Dr. W. A. Nagel describes peculiar 
structures sunk in the epithelial folds of the siphon of Gardium 
dblongum. They are externally like other siphonal papilla}, but show 
a weakly developed epithelium and no internal nuclei, only a coarsely 
fibrous substance, composed of coiled threads apparently non-contractile. 
There is no evidence of sense-cells nor secretory elements. A study of 
fresh specimens is desirable. 
Arthropoda. 
a, Insecta. 
Autotomy in Phasmidae.f — M. Edmond Bordage describes autotomy 
in the larvae, nymphs, and adults of Monandroptera inuncans and Blia- 
pJiiderus scabrosus. In the larvae it occurs very readily ; in the nymphs 
it becomes increasingly difficult in proportion as they draw nearer the 
final metamorphosis ; in the adults it is capricious, and never so easily 
produced as in the saltatory Orthoptera. The anterior limbs are usually 
those which are most readily detached. While in the grasshoppers it 
is the contraction of a single muscle or of a small number of muscles 
that causes the rupture ; this requires in the Pliasmidae very vigorous 
muscular contractions affecting the entire body, and is associated with 
serious haemorrhage. 
Life-History of Halictus.§ — Dr. C. Verhoeff has made an interest- 
ing study of the life and habits of Halictus ( Anthophila ), especially of 
JET. quadristrigatus. The vault or dome made by this species over the 
comb is constructed when the first batch of 1-5 cells has been formed. 
From 4-19 cells are made, and the number is in every case determined 
by the space afforded by the vault. The comb is freely surrounded by 
air. After laying the last egg and closing the last cell the mother bee 
does not die ; she lives on until the larvae are full-grown. But although 
she may come to know the first of her progeny, their appearance is a 
sign for her death. She broods on the comb from the dorsal side, to 
which the larvae are turned, and where the cell- walls are thinner than 
elsewhere. The vault serves to protect the.newly hatched young, and 
* Ann. Sci. Nat. (Zool.), iv. 1896 (1897) pp. 221-52 (2 pis.). 
f Zool. Anzeig., xx. (1897) pp. 406-9 (2 figs.). 
% Ann. Nat. Hist., xx. (1897) pp. 473-8; Comptes Rendus, cxxiv. (1897) 
pp. 210-2, 378-81. § Zool. Anzeig., xx. (1897) pp. 369-93 (21 figs.). 
