XXVll 



obscurus, North America; Cyclidius velutinits ; Cremastocheilas crassipes, 

 California; and Pantodinus Klugii, Guatemala. 



Prof. Westwood called the attention of the Society to a letter in ' Nature' 

 (Nov. 1st, 1877, p. ] 1), from Mr. J. Saville Kent, a propos of Mr. Wood- 

 Mason's discovery of stridulating appa^'atus in scorpions, announced to the 

 Society at the September meeting, and from which letter the following is an 

 extract : — 



"The Crustacean in question, which I have ascertained to possess 

 sound-producing properties to an eminent degree, is a species of Spheroma, 

 belonging to the isopodous order of the class. I have not as yet ascertained 

 the exact method in which sound is produced, nor whether the animal has 

 organs specially adapted for the purpose : on numerous occasions, however, 

 my attention has been attracted to the glass jar of which, with the exceptiou 

 of microscopic Copepods and Protozoa, a single specimen of the species is 

 the sole animal occupant,, by a little sharp tapping sound produced three or 

 four times consecutively, with intervals of about one second's duration, and 

 which I can almost exactly imitate by gently striking the side of the jar 

 with the pointed end of a pipette. On being approached the little creature 

 always endeavours to elude notice by passing to the opposite side of the stalk 

 of sea-weed upon which it usually reposes, in the same way that a squirrel 

 dodges round the branch of a tree ; and on no occasion, so far, have I been 

 able to catch the little fellow flagrante delicto, or in the act of producing 

 the sound which it most undoubtedly emits. The character and intensity 

 of the sound produced, associated with the small size of the animal, 

 scarcely one quarter of an inch in length, induces me to believe that it 

 is caused by the sudden flexion and extension of the creature's body." 

 Mr, Kent also mentions the snapping sound produced by Alpheus ruber 

 and the "shrill squeaking sound" emitted by the large sea crayfish 

 [Palinurus qicadriconiis) when handled, this sound being produced '.'by the 

 rubbing together of the spinous abdominal segments." 



Mr. Wood-Mason remarked that structures in Crustacea, some of which 

 certainly, and all of which probably, are for the production of sounds, were 

 first brought to notice by Hoffmann, — in V. der Decken's ' Reisen in Ost- 

 Africa (Crustacean)' — but had been independently observed by himself in a 

 number of species during his dredging excursion to the Andaman Islands 

 in 1872. Tliey were paired organs, as in Scorpions, the Mygale, and the 

 Phasma to be brought to notice that night — that is to say, organs working 

 perfectly independently of each other were on each side of the body. In 

 some forms (I.) they were seated partly on the body (carapace) and partly 

 on a pair of appendages ; of these some {a) had the acraper on the body and 

 the rasp on the appendages — e.g., Maluta, in which tlie organs are developed 

 in both sexes ; and others (b) bad the rasp on the body and the scraper on 

 the appendages — e.g., MacrupUlhahnus et atrniia, in which the scraper was 



