sponge and the Sponge Fishe7''ies. 165 



Levant and off the Syrian and Tripoli coasts, are found 

 between the average aerial winter temperature of 63° and 

 70°, and the isochrymals of 50° — 57°, and at no time of the 

 year are these, which, as stated, by Von Eckhel, occur in 

 the deeper water at a distance from the coast, probably ex- 

 posed to a lower temperature than 60°. 



In describing the species of this genus I have made 

 comparisons between three principal Mediterranean and 

 three of the American commercial sponges, in order to 

 show the very evident relationship of these forms. Schmidt 

 describes five Mediterranean species in all, and may be 

 right ; but so far as I can understand his descriptions, with 

 the aid of a fine collection of specimens purchased by Pro- 

 fessor Baird for the National Museum from Mr. Isaacs, of 

 New York, I cannot make more than three out of the ordi- 

 nary commercial varieties, which were fully represented, and 

 appeared to include the entire range of his five species. 

 Von Eckhel's work upon the " Badeschwamme," although 

 a purely commercial treatise, has the same view of the 

 affinities of the sponges, based upon the observations of the 

 fishermen and dealers, and the distribution of the species. 

 The latter is quite remarkable. Only one species, the 

 Spongia officinalis, Lin., Adriatica, Schm., is found on the 

 eastern shore of the Adriatic and coast of Greece, from 

 Trieste to the Bay of Nauplia. From Nauplia and the 

 island of Candia to Eritra, on the coast of Asia Minor, two 

 occur, Spongia officijialis and Spongia agaricana, Pall., 

 Zimocca, Schm. From Eritra, opposite the island of Chios, 

 to Tripoli, all three, Spongia officinalis, agaricana, and equina, 

 are fished, except at the island of Cyprus, where the 

 zimocca sponge does not live. From Tripoli to Tunis two 

 only occur, Spongia officinalis and equina, and from thence 

 to Ceuta, at the Straits of Gibraltar, a very peculiar dark- 



