142 NOTES AND MEMORANDA. 



Brain of Invertebrates. — M. Dietl has two important papers 

 on this subject in the ' Proceedings of the Vienna Academy,' * in the 

 first of which he describes the brains of Eledone, Sepiola, and Tethys, 

 and in the second that of Astacus and Squilla. The former is illus- 

 trated by nine plates, the second by one plate. The papers consist 

 entirely of detailed descriptions of the brains in question, and do not 

 readily admit of abstracting. We are therefore reluctantly obliged 

 to confine ourselves to the record of their publication. 



Poison Apparatus and Anal Glands of Ants. — Dr. August Forel 

 gives in the ' Zeitsch. fiir wiss. Zoologie ' f an exhaustive account, with 

 two plates, of these structures. He first gives an account of the sting 

 in the Formicidce, stating that in his Section a of that family the 

 organ is quite rudimentary, while in Section /3, although very small 

 and delicate, it has all the structure of the sting of Myrmicidce and 

 Pone7-idce. 



Of the poison apparatus, consisting of gland and receptacle, there 

 are two types, one found in Section a of Formicidce, the other in 

 Section /3 of that family and in all other ants. From this circum- 

 stance, as well as from the structure of the sting, Forel proposes to 

 divide Formicidce. into two sub-families, Camponotidce (Section a), and 

 Bolichoderidce (Section /3). The types are distinguished as (1) poison- 

 bladder with pad {Polster) ; and (2) poison-bladder with knob 

 {Knopf). 



(1.) In the first type the poison-bladder is elongated and widened 

 and provided with a duct of but little less diameter than itself. Its walls 

 consist of a tunica intima bounding its cavity, then of a layer of pro- 

 toplasm with scattered nuclei, representing an epithelium, and finally 

 of an outer tunica propria containing muscular fibres. On its dorsal 

 side, between the intima and j^ropria, is a large flattened cushion- 

 like body, the pad, consisting of a greatly coiled, branched or un- 

 branched chitinous tube, the coils being separated from one another by 

 a layer of nucleated protoplasm. Although the pad itself is not 

 more than 2 mm. long, the tube may attain a length of 20 mm. At 

 one end the tube opens into the bladder, with the intima of which 

 the edges of the aperture are continuous. At the other end, situated 

 posteriorly or xmder the duct of the bladder, it is connected with a 

 pair of glandular filaments, lying external to and on the dorsal side of 

 the bladder. These filaments are the free portion of the poison- 

 gland, the coiled tube of the pad with its protoplasm constituting its 

 intra-vesicular portion. The free gland-cpeca consist of a layer of 

 epithelial cells, covered by a tunica propria continuous with that of 

 the bladder, and lined by an intima, bounding the lumen, and sending 

 off very fine lateral tubes to the individual gland-cells. 



(2.) In the second type the poison-bladder is small and nearly 

 globular, and its duct is a fine tube with walls thrown into trans- 

 verse folds. The free portions of the poison-gland are shorter and 

 thicker than in the first type ; the united portion, answering to the 



* ' Sitzungsberichte der (Wiener) k. Akad. der Wiss.,' vol. Ixxvii. (1878), 

 1st Alith. p. 481. 



t ' Zeitsch. f. wiss. Zool.,' vol. xxx. (Suppl.), (1878), p. 28. 



