512 PROCEEDINGS OF THE NATIONAL MUSEUM tol. 91 



an acute, flattened, corneous spine ; anterior margin below spine about 

 straight ; ventral angle rounded off. 



Holotype. — The largest of seven specimens (5 males and 2 females), 

 a male measuring 26.6 mm. in median length of carapace and rostrum 

 together, U.S.N.M. No. 79079. The smallest specimen is also a male 

 and measures about 11 mm. in median length of carapace and 

 rostrum. The specimens were collected by Dr. C. H. Eigenmann 

 at Abtao, Chile, February 22, 1919. 



Remarhs. — See under A. riollmayana^ "Remarks," p. 515. 



Distribution. — ^With certainty at present known only from the type 

 locality, Abtao, Chile. An unmistakable representative of the species, 

 an untagged male of 28.0 mm. in length of carapace and rostrum, 

 was found along with several other specimens in a bottle of material 

 borrowed from the Buenos Aires Museum. One was the type of 

 A. afpnis (M.A.C.N. No. 9817), another an unattached cheliped of 

 the same species (tagged M.A.C.N. No. 4186), and an untagged 

 female of A. hwnahuaca (22.0 mm. long). In the catalogs of the 

 Museo Argentino Ciencias Naturales entry No. 4186 reads simply, 

 "Neuquen, Mayo 16, 1898; Sr. Carlos Burmeister"; entry No. 9187 

 concerns specimens of Mytilus chonis Molina received in exchange 

 from Dr. Carlos S. Eeed, 21-V, 1919. The bottle contains a mixture 

 of things, or else a misattached label or labels, and to the untagged 

 specimens no locality at all may be safely attached. 



Further, I have before me a small male of 19.5 mm. in length of 

 carapace and rostrum together, also collected by Dr. Eigenmann in 

 Chile, "Falls of Petrohue," March 8, 1919. Although this particular 

 specimen has been only tentatively placed with A. abtao, it is prob- 

 ably correctly determined ; the rostrum seems a bit more slender than 

 typical A. abtao, the areola perhaps a bit narrower and the ventral 

 inner margin of the ischium somewhat smoother. 



Almost too late for mention, I received a very fine, dried example of 

 this species from Dr. Carlos A. Porter. It measures 26 mm. in length 

 of carapace and rostrum and was collected by Dr. Porter himself, in 

 December 1941, near "El Valean," Santiago, Chile. The rostrum fits 

 the description of the type almost exactly ; indeed this specimen is a 

 very close counterpart of the type. The lobular tooth on the fixed 

 finger of the minor right cheliped is no more in evidence than in the 

 type (fig. 63, a) . However, the conical tubercles on the dorsal longi- 

 tudinal margin of the merus of the cheliped appear single-spined or 

 spinule-tipped ; the inner ventral margin of the ischium is as in the 

 type on the right cheliped ; on the left one there are two small eleva- 

 tions of which the anterior is the larger and small spinule-tipped 

 between the anterior and posterior spines. The anterior dorsal angle 

 of the epimeron of the second abdominal somite is armed with two 

 small spines or spinules on the left side, with one only on the right. 



